Koryo (高麗)

The collapse of the United Silla resulted in endless hostilities between the emerged smaller states, Silla, Hupaekche and Taebong. The population suffered a lot, leading to unrest. The majority of the ruling class desperately needed stability and demanded unity in the country. In the neighboring China, Tang Dinasty fell down and the situation was very disturbing. Khitan tribes that established their own state in East-North of China in 916 AD, also threatened Koreans. Without unification Koreans would not be able to defend the borders. 

In 918 AD, a powerful feudal lord and landowner Wang Geon from Taebong declared himself the King and established the state Koryo, the shortened version of Koguryo. Two years later, Silla became Wang Geon's ally, and 15 years later, Silla's territory joined Koryo. Next year after that Wang Geong's army with 100 thousand troops defeated Hubaekche and took its territory as well, completing the unification of the country. 

The capital of Koryo was built in Kaegyong (modern Kaesong), where Wang Goen came from. All officials in the country was divided into two groups, civil and military. That's why they both was called yangban (two groups). This word is used nowadays too, meaning any aristocratic person.

Pyongyang was playing an important role for expanding the country in the Northern direction, and the city was renamed as Seogyong (Western Capital). Former Silla's main city Kyongju became Tonggyong (Eastern Capital), and former Paekche capital Yangju was called Namgyong (Southern Capital). By the end of the 10th century AD, Koryo became the most stable and centralized state on the Korean peninsula. 

Having made China under Song Dynasty its main trade partner, Koryo was exporting there gold and silver, silk, ginseng, porcelain, paper and furs. Import mainly consisted of the Chinese high quality textile, medicines, calligraphy brushes and souvenirs. Some trade was developed with Khitans and Jurchens as well as Japanese. For the first time in history, metallic coins called kwan were introduced in Korea. 

At the early 13th century, a new threat emerged on the Koryo's border, when Mongols with their leader Genghis Khan conquered Northern China. Khitans frequently attacked Koryo's fortresses until 1218, when about 10 thousand Mongolian troops and 20 thousand soldiers from Dongzhen state entered Korean territory by order from Genghis Khan to defeat Khitans and to establish "friendly relations" with Koryo. In reality, Mongols demanded Koreans to be vassals and pay tribute. Koreans was very upset with the situation and killed a Mongolian ambassador when he was trying to collect a current part of tribute. Mongols cut the relations with Koryo but left it without retaliation. Genghis Khan died in 1227. Three years later, an army headed by Mongolian general Saritai attacked Koryo. To defend the country many rebels joined the government forces. 

As it mentioned in "Koryo-sa" (History of Korea), "a leader of bandits from  Masan Mountain came to (Choi) U and bended his head, saying: Let me help you to defeat Mongols with my 5000 troops. U was very pleased and rewarded him generously... U also sent his man to Kwangju to persuade robbers, who had infested Kwanak Mountains. Five gang leaders and 50 best fighters were largely rewarded and enrolled in the Right Army". 

In 1232, Mongols agreed to deal a peace treaty with Koryo, demanding huge amount of tribute, that included one million sets of cloth, 10 thousand pil of silk, 20 thousand furs, 20 horses and two thousand young men and girls from noble families. Partly Koryo had paid the tribute, and Mongols left the country leaving there only their vice-regents to keep Koreans under control. Again, Koreans felt very unhappy with the situation, and the noble governor Choi U decided to put an end to dependence from Mongols. The vice-regents were killed and the capital was removed to Kanghwa Island. The place was a refuge for the Koryo rulers to escape from invasions which the people of the rest of the country had faced. Many years Koreans had been defending their lands. In 1258 a revolt brought to power mutineers headed by Kim In-Jung, who decided to stop resistance to Mongols. Koryo's King Kojong died and the new monarch Wonjong turned out to be a zealous follower of the Mongol's policy. 

Situation in the country worsened by ravages and hunger, many people died and cases of cannibalism were reported in old chronicles. Soldiers from the so called "Three special corps" - Sambyolcho, formed an army of resistance, mostly consisting of peasants and slaves. They moved south from Kanghwa Island and soon occupied islands Jindo and Jeju (Quelpart). In 1271, the army of Sambyolcho conquered more islands and some territories of the provinces Kyongsan, Jolla and Chunchon. King Wonjong and Mongols was trying to put an end to the rebelion. In 1273, ten thousand Mongol's troops crashed the army of Sambyolcho on Jeju Island. Mongols then made the vast land at the very end of the Korean peninsula a huge pasture for their horses.  

After Khubilai Khan established Yuan Empire in China, he refused to conquer Koryo keeping in memory the history of Korean resistance. It was considered enough to have Koryo as a vassal state. To strengthen ties, Koryo Kings had to marry only Mongol princesses. Some Yuan's Emperors also had found wives in Koryo. Together with Mongol army Koreans were mobilized to attack Japan. Twice such efforts took place in 1281, but without success. Moreover, the defeat in these campaigns gave a tremendous impact on Koryo. Mongol's interference in the affairs of Koryo was a destruction for the state system.  

In the middle of the 14th century, Yuan Empire began to fall apart. "Red turban" rebellion overrun Mongols in China and established a new dynasty Ming. In Korea, the King Kongmin, who took power in Koryo in 1351, cancelled some laws and rules, introduced under the Mongol's rule. In a few years Koryo managed to liberate Jeju Island and other areas occupied by Yuan. But "red turbans" turned out to be the new threat to Koryo, attacking its lands and facing fierce resistance from local people. In 1369-1370 Koryo's army headed by General Lee Song-gye (Yi Song-gye) twice had made raids to areas of South-East China, eliminating local rulers who tried to invade Koryo's soil. This helped a little to achieve stability on the boarder but another problem was caused by Japanese pirates in the South. They killed hundreds of Koreans, took their belongings and food products. 

Lee Song-ge group was seeking to revive centralized system and state's land ownership. For the reforms he needed to overcome resistance of the group of Confucian scholars headed by Jong Mong-ju (Chong Mong-ju). In 1392, when Lee was sick after he fell from his horse, Jong came to visit his rival to find out the situation.  Lee's son Bang-won tried to convince Jong Mong-ju to defect to their group, but unsuccessfully. By pretext that Jong was allegedly was making a plot against Lee, they sent killers and took Jong Mong-ju's life.

It happened on Songjuk-kyo stone bridge in Kaesong, that still exists there, and a brownish spot is visible on one of the stone plates of the bridge. People say, this is the blood of Chong Mong-ju, who kept his loyalty to the King.

After killing the opponent of the reformers, Lee Song-gye took the throne in 1392, starting the new Dynasty of Lee, which then ruled the country for more than 500 years.  

One of Lee Song-gye's sons Bangwon became the King known under the name of Taejong in 1401, and in 1419 he was succeeded by King Sejong, who ruled till 1450. The reign of the two was the period of strengthening Koryo state. In 1393 the country was renamed as Choson and soon after that the capital was relocated to Seoul.